It’s not set in stone yet. This may or may not become widely available to all advertisers, but I’d be surprised if it didn’t open up to a wider set. Here’s what the ads look like:

Notice the “privacy” link. If you click that, it says, “When you submit this form, your email address will be sent to the advertiser.”

The testing has been going on for a little while, but from the sound of it, it’s expanded a bit. Alexia Tsotsis at TechCrunch shared the following statement from a Google spokesperson:

“We’re currently running a small experiment of a new ad format that helps users sign up more easily for email subscriptions or other free newsletters. This new ad format contains a box within the ad that displays a user’s Google email address (if logged in). If a user chooses to click ‘Subscribe to newsletter’ then the email address is sent to the advertiser directly, which is clearly disclosed within the ad itself.”

Some email marketing firms like VerticalResponse, Constant Contact and AWeber are already using the ads.

While social networking continues to rise, email and search are still the most popular online activities, and these new ads take advantage of both. Look at this graph Pew put out a few months back. You can see how social media is growing, but look at how search and email are doing.

Social is not killing email, by any means.

But, interestingly enough, there is still a social element to these ads as well - the +1 button. Really, you’re getting the best of all three worlds (OK, maybe not the “best”. it would probably be better if they also had Facebook like buttons, retweet buttons, and StumbleUpon butons alongside the +1, but Google+ is growing like a weed, and the +1 has ramifications for organic search ranking).

These ads could be the best search-driven tool for driving email sign-ups ever available. We’re talking prime real estate on Google SERPs to drive an opt-in path directly to people’s inboxes.

This will no doubt be an incredibly popular ad format for Google, and I can’t imagine them not making it widely available.

Really, it should be a great thing for the entire email marketing industry. It may never even occur to people searching for various topics that there are even email newsletters related to what they’re looking for. They simply may never have thought to look for one. These ads will put them directly in front of users’ faces. This could very well lead to a lot more content being consumed by email at a time when many have suggested that social networks would all but kill the channel (clearly this is not happening).

Think about it. Let’s say you are a huge fan of the Detroit Lions (full disclosure: this applies to me). What if you were searching for Lions-related content on Google, only to discover that there is an amazing newsletter about the team that you had no idea existed. You might want to sign up for that.

Do you use email marketing? Would you purchase these ads on Google? Let us know.